1 files changed, 143 insertions, 0 deletions
diff --git a/railties/lib/rails/command/base.rb b/railties/lib/rails/command/base.rb
new file mode 100644
index 0000000000..7ae190433a
--- /dev/null
+++ b/railties/lib/rails/command/base.rb
@@ -0,0 +1,143 @@
+require "thor"
+require "erb"
+
+require "active_support/core_ext/string/filters"
+require "active_support/core_ext/string/inflections"
+
+require "rails/command/actions"
+
+module Rails
+  module Command
+    class Base < Thor
+      class Error < Thor::Error # :nodoc:
+      end
+
+      include Actions
+
+      class << self
+        # Returns true when the app is a Rails engine.
+        def engine?
+          defined?(ENGINE_ROOT)
+        end
+
+        # Tries to get the description from a USAGE file one folder above the command
+        # root.
+        def desc(usage = nil, description = nil, options = {})
+          if usage
+            super
+          else
+            @desc ||= ERB.new(File.read(usage_path)).result(binding) if usage_path
+          end
+        end
+
+        # Convenience method to get the namespace from the class name. It's the
+        # same as Thor default except that the Command at the end of the class
+        # is removed.
+        def namespace(name = nil)
+          if name
+            super
+          else
+            @namespace ||= super.chomp("_command").sub(/:command:/, ":")
+          end
+        end
+
+        # Convenience method to hide this command from the available ones when
+        # running rails command.
+        def hide_command!
+          Rails::Command.hidden_commands << self
+        end
+
+        def inherited(base) #:nodoc:
+          super
+
+          if base.name && base.name !~ /Base$/
+            Rails::Command.subclasses << base
+          end
+        end
+
+        def perform(command, args, config) # :nodoc:
+          command = nil if Thor::HELP_MAPPINGS.include?(args.first)
+
+          dispatch(command, args.dup, nil, config)
+        end
+
+        def printing_commands
+          namespace.sub(/^rails:/, "")
+        end
+
+        def executable
+          "bin/rails #{command_name}"
+        end
+
+        # Use Rails' default banner.
+        def banner(*)
+          "#{executable} #{arguments.map(&:usage).join(' ')} [options]".squish!
+        end
+
+        # Sets the base_name taking into account the current class namespace.
+        #
+        #   Rails::Command::TestCommand.base_name # => 'rails'
+        def base_name
+          @base_name ||= begin
+            if base = name.to_s.split("::").first
+              base.underscore
+            end
+          end
+        end
+
+        # Return command name without namespaces.
+        #
+        #   Rails::Command::TestCommand.command_name # => 'test'
+        def command_name
+          @command_name ||= begin
+            if command = name.to_s.split("::").last
+              command.chomp!("Command")
+              command.underscore
+            end
+          end
+        end
+
+        # Path to lookup a USAGE description in a file.
+        def usage_path
+          if default_command_root
+            path = File.join(default_command_root, "USAGE")
+            path if File.exist?(path)
+          end
+        end
+
+        # Default file root to place extra files a command might need, placed
+        # one folder above the command file.
+        #
+        # For a `Rails::Command::TestCommand` placed in `rails/command/test_command.rb`
+        # would return `rails/test`.
+        def default_command_root
+          path = File.expand_path(File.join("../commands", command_name), __dir__)
+          path if File.exist?(path)
+        end
+
+        private
+          # Allow the command method to be called perform.
+          def create_command(meth)
+            if meth == "perform"
+              alias_method command_name, meth
+            else
+              # Prevent exception about command without usage.
+              # Some commands define their documentation differently.
+              @usage ||= ""
+              @desc  ||= ""
+
+              super
+            end
+          end
+      end
+
+      def help
+        if command_name = self.class.command_name
+          self.class.command_help(shell, command_name)
+        else
+          super
+        end
+      end
+    end
+  end
+end